Patent GB-483823-A (GB)
Title: Manufacture of halogenation products
IPC: C07B39/00
Filed: 1936-09-25
Abstract: <PICT:0483823/IV/1> <PICT:0483823/IV/2> In halogenating organic compounds, a gaseous halogenating agent is blown through a capillary into a narrow tube in countercurrent to the liquid organic compound flowing through the tube. Halogenation may be effected in the presence of a catalyst. Products containing in the molecule one halogen atom more than in the parent material can be obtained nearly quantitatively.  The following substances may be monohalogenated: propane, butane, isobutane, the isomeric pentanes, hexanes, heptanes, octanes, dodecanes and mixtures of the isomeric products, benzene, toluene, xylene, molten naphthalene, acetone, methyl ethyl ketone, di-isopropyl ketone, cyclohexanone, methylcyclohexanone, benzophenone, acetophenone (in the presence of a catalyst, the halogen enters the nucleus; in the absence of a catalyst, it enters the side chain), glacial acetic acid, propionic acid, butyric acid, and isobutyric acid.  A further halogen atom may be introduced into the monohalogen derivatives of these parent materials.  Suitable halogenating agents are chlorine, bromine, and sulphuryl or thionyl chloride or bromide.  Suitable halogenation catalysts are ferric, antimony and sulphur chlorides. The reaction zone may be exposed to actinic light.  Reaction may be effected at a temperature just below the boiling point of the parent material or at 0 DEG  C., or higher. In an example, benzene is boiled in still 1, the vapours ascending a column 2 provided with a dephlegmator, and condensing in a Woolf's bottle 3.  The benzene flows through tower 9 filled with ferric chloride and then descends through a vertical tube 4 having an overflow 10 and a constricted portion 8 in which it meets chlorine introduced through capillary 5.  The constricted portion is shown in detail in Fig. 2, the benzene accumulating in the annular space 7 and flowing down the walls of the tube 8.  The diameter of the capillary 5 may be 1 mm. and that of tube 8 not more than 150 mms. Hydrochloric acid escapes through tubes 4 and 11 and condenser 6. The monochlorbenzene and excess benzene flow to the still 1 through a siphon.  Other examples relate to the use of the same or similar apparatus in (1) the treatment of pentane at 20-30 DEG  C. with chlorine; (2) the treatment of glacial acetic acid at 90-100 DEG  C. with bromine vapour, sulphur chloride being used as a catalyst; (3) the treatment of glacial acetic acid at 90-100 DEG  C. with chlorine, sulphur chloride being used as a catalyst; (4) the treatment of a petroleum fraction, boiling between 100 and 125 DEG  C. and consisting chiefly of heptanes, at 30-70 DEG  C. with chlorine. When most of the mixture of heptanes has been chlorinated, the reaction product is fractionally distilled.  In another example, preheated cyclohexane is introduced through a cylinder mounted at the head of a column in which chloro-cyclohexane is maintained at 130-140 DEG  C. The cyclohexane vapour is condensed in a Woolf's bottle, and the liquid chlorinated as in the other examples.  The chlorination product is continuously removed from the still and purified by simple distillation.